Regulating random mechanical motion using the principle of
auto-winding mechanical watch for driving TENG with constant AC
output – An approach for efficient usage of
high entropy energyNano Energy 87 (2021) 106195
Available online 27 May 2021 2211-2855/© 2021 Elsevier Ltd. All
rights reserved.
Full paper
Regulating random mechanical motion using the principle of
auto-winding mechanical watch for driving TENG with constant AC
output – An approach for efficient usage of high entropy
energy
Gaofa He a,*, Yingjin Luo a, Yuan Zhai b, Ying Wu b,*, Jing You a,
Rui Lu a, Shaokun Zeng a, Zhong Lin Wang c,d,**
a School of Mechanical and Power Engineering, Chongqing University
of Science & Technology, Chongqing 401331, China b School of
Intelligent Technology and Engineering, Chongqing University of
Science & Technology, Chongqing 401331 China c Beijing
Institute of Nanoenergy and Nanosystems, Chinese Academy of
Sciences, Beijing 101400, China d School of Materials Science and
Engineering, Georgia Institute of Technology, Atlanta, GA
30332-0245, United States
A R T I C L E I N F O
Keywords: Environmental Energy Harvesting Mechanical Control
Constant output Low-Frequency and Random Excitation Triboelectric
Nanogenerator
A B S T R A C T
The world is fulfilled with low-quality, irregular, and widely
distributed energy, but highly efficient harvesting of such
high-entropy energy is hardly possible due to the limitation of
currently existing technologies. Recently, triboelectric
nanogenerators (TENGs) were invented to harvest random and ambient
mechanical energy, and have shown wide applications because of
their high efficiency and low-cost. However, the output of the TENG
is dictated by the irregularity of the input mechanical agitation.
This paper reports a mechanical regulator using the principle of
auto-winding mechanical watch for driving the triboelectric
nanogenerator with constant AC output (Constant Output TENG,
CO-TENG). The device which comprised energy harvest and storage
module, energy controllable release module, and energy conversion
module can achieve energy harvesting-storage-release not only
steadily but also continually under even low-frequency (0.5 Hz) and
random working stimulation. The CO- TENG has been successfully
applied to harvest the energy of random waves, wind, and water
flows, through the adjustment of the input gear train and energy
collection parts, such as water turbine, wind scoop, and
oscillating buoy. The CO-TENG can steadily and continually produce
an open-circuit voltage of 550 V, a short-circuit current of 6 μA,
and transferred charges of 190 nC under low-frequency and random
mechanical stimulation. With the rectifier filter, a commercial
thermometer and 450 LEDs in serial connection were separately
powered by the CO-TENG. It demonstrates that the CO-TENG is a
potential solution for effective usage of high entropy energy that
has a random amplitude and irregular low-frequency.
1. Introduction
With the development of Microelectromechanical systems (MEMS) and
Internet of Things (IoT) technology, microelectronic monitoring
equipment have shown broad application prospects in the fields of
human health, environment and military monitoring [1–5]. However,
power supply adapted to microelectronic monitoring equipment be-
comes a new challenge, especially for wireless usage in forests
[6], oceans [7] and other similar uninhabited wild environments.
Tradi- tionally, these devices are powered by various chemical
batteries, such as dry, lithium batteries or others, which will be
replaced or charged
frequently because of their limited capacity. This not only
increases costs of long-term use, but also brings serious
environmental pollution. To avoid these problems, a potential
solution is to harvest ambient mechanical energy to supply power
for monitoring devices [8–10]. Triboelectric nanogenerators
(TENGs), invented by Wang’s group in 2012, is a new nano-energy
technology by coupling of tribo- electrification and electrostatic
induction [11–15]. Compared with the electromagnetic induction and
piezoelectric effect [16,17], TENGs are regarded as outstanding
solutions for transformation from low-frequency mechanical energy
into electric energy with advantages of microminiaturization,
application scenario diversification and simple
* Corresponding authors. ** Corresponding author at: Beijing
Institute of Nanoenergy and Nanosystems, Chinese Academy of
Sciences, Beijing 101400, China.
E-mail addresses:
[email protected] (G. He),
[email protected] (Y. Wu),
[email protected] (Z.L.
Wang).
Contents lists available at ScienceDirect
Nano Energy
2
manufacturing process [18–21]. In recent years, the reports of
using TENGs to collect mechanical
energy in the environment (such as wind [22–24], water flow
[25–27], waves [28–31], various objects and organisms [32–34]) are
very active. There are still some disadvantages in practical use,
because the external excitation generated by the ambient mechanical
energy is random or irregular in amplitudes, direction, and/or
frequency [35–37]. To effec- tively harvest low-quality, irregular,
and widely distributed energy such high entropy energy [38], many
scholars have done a lot of research work. Xia et al. demonstrated
a water balloon TENG that can harvest all-weather water wave energy
[39]. Lu et al. developed a TENG, which can realize entire stroke
energy harvesting by the bidirectional gear [40]. Feng et al.
designed cylindrical TENG that can efficiently harvest
ultra-low-frequency water wave energy by the swing structure [41].
Chen et al. proposed a chaotic pendulum TENG to harvest wave energy
[42]. Cheng et al. developed a TENG based on a cam and a movable
frame to realize ambient mechanical energy harvesting [43].
Although these cleverly designed TENGs generated electrical energy
under low-frequency and random excitation, the output electrical
energy is often random and disordered, or it disappears as soon as
the external excitation stops. Bhatia et al. designed a random
energy harvest device using a flat spiral spring that can achieve
outstanding electrical output in the external excitation range of
0–50 Hz [44]. Yin et al. demonstrated a mechanical regulation TENG,
which realized controllable and quanti- tative output of random
energy [45]. Wang et al. proposed an impact energy harvesting
system using a mechanical vibration frequency sta- bilizer that can
maintain the output frequency stabilization with a variation of 33%
when the input frequency changed by 436% [46]. All of these
researches have worked on the storage of random vibration energy.
However, the methods to control the energy releasing are not
considered enough. For example, the speed of the rotor that is
powered by the elastic potential energy of the spiral spring is
unsteady due to the mismatch between the flywheel inertia and the
frictional resistance, so that the energy output is intermittent
and discontinuous. Therefore, to
efficiently harvest energy from random external excitation in
natural environment, an excellent mechanical energy-electricity
transformation system that can independently realize steady power
energy of harvest-storage-release is required.
In this paper, we present a mechanical regulator using the
principle of auto-winding mechanical watch for driving the
triboelectric nano- generator with constant AC output (Constant
Output TENG, CO-TENG) under low-frequency and random excitation.
The auto-winding me- chanical watch is a device that stores random
arm swing energy into potential energy, which is regularly released
to drive the watch at a designed operation pace. The device
consists of three parts: Part I - en- ergy harvest and storage
module, composed of input shaft, input gear train, and flat spiral
spring (spiral spring), for converting various random environment
energy, such as waves, water flow, and wind, to elastic potential
energy of the spiral spring, through the replacement of the input
gear train and energy collection parts, respectively water turbine,
wind scoop, and oscillating buoy. Part II - energy controllable
release module, consisted of escapement-spring-leaf and
transmission gear train, controls elastic potential energy of the
spiral spring released with a constant velocity by the
escapement-spring-leaf. The working principle of the
escapement-spring-leaf is like the escapement mecha- nism of the
auto-winding mechanical watch. Part III - energy conversion module,
made up of output gear train, one-way shaft system, flywheel, and
TENG transmission unit, translates the mechanical kinetic energy to
electric energy, continuously and steadily.
2. Experimental section
2.1. Fabrication of the CO-TENG
The CO-TENG mainly comprises three parts: energy harvest and
storage module, energy controllable release module, and energy con-
version module. The gears and gear support involved in each
component are made of acrylic materials and processed by laser
engraving (X-7050,
Fig. 1. Structure and working principle of the CO-TENG. (a) Working
principle of CO-TENG; (b) motion transfer process of CO-TENG; (c)
electric energy conversion processes; (d) operating principle of
the escapement-spring-leaf mechanism; (e) floor plan of CO-TENG;
(f) picture of whole structure of CO-TENG.
G. He et al.
3
G.U. EAGLE, Beijing). The spring barrel, limit pile, ratchet, and
escapement lever are made of polylactic acid (PLA) and fabricated
by the 3D printer (RT-JD200, RUITE 3D, Xi’an). The base plate and
each drive shaft are fabricated with aluminum alloy, which is made
by CNC machining (M-V70En, Mitsubishi Heavy Industries, Japan). The
TENG transmission unit comprises two parts: the stator and the
rotor. Six copper electrodes with 50 mm (length) × 50 mm (width) ×
50 µm (thickness) apply to the inner of the stator. Three flexible
films are FEP films, which attached to a rotor, with 65 mm (length)
× 50 mm (width) × 50 µm (thickness).
2.2. Characterization and measurements
A stepping motor (ECMA-CM1306PS, DELTA, Shanghai) provides external
excitation for the wave pool. An air compressor (OLF-3540, FENGBAO,
Shanghai) was used to make breeze and the wind speed was obtained
by an anemometer (ST8816, SMART SENSOR, Hong Kong). A submersible
pump (HLW-400, SUNSUN, Zhejiang) was used to generate water flow
and the flow rate was obtained by a kinemometer (LJ20B, XIANGRUIDE,
Nanjing). Moreover, a programmable electrometer (6514, Keithley,
USA) and a Data Acquisition Card (USB-6251, National Instruments,
USA) was used to test open-circuit voltage, short-circuit current,
and transferred charges, and the rotor speed was captured by a
non-contact tachometer (VC6236P, Victor, Shenzhen). Finally, the
measured data can be saved and analyzed on LabVIEW.
3. Results and discussion
3.1. Structure and working principle of the CO-TENG
Fig. 1 show the working principle, overall and partial detailed
design and display of the CO-TENG. Fig. 1a depicts the working
principle of the CO-TENG. The vertical movement of the wave after
transmission, compresses the spiral spring to collect mechanical
energy, and then the spiral spring will drive the rotor of TENG
with controlled by the escapement-spring-leaf mechanism like the
principle of auto-winding mechanical watch.
The motion transfer process of the CO-TENG is illustrated in Fig.
1b. The power of the energy-harvest unit drives the spiral spring
shaft to rotate by the gear pairs Z11-Z12 and Z21-Z22 (The spiral
spring shaft bearing is one-way bearing, which ensures that the
spiral spring shaft can only rotate in clockwise. Gear Z21 is
behind the gear Z12, and not be shown in the Fig. 1b.) and compress
the spiral spring and convert random environmental energy into
elastic potential energy storage of the spiral spring. The gear
Z31, which is rigidly connected with the spring barrel and driven
by the spiral spring, rotates clockwise and en- gages with the gear
Z32, thus driving the ratchet Z41 and gear Z33. The escapement
lever Z42 can open and close intermittently under the drive of the
gear Z41, then the energy of the spiral spring is controlled and
released by the frequency of the escapement lever Z42. The spiral
spring energy which was controlled by gear Z32 drive gear Z33
intermittent rotation, through a one-way bearing (installation
between gear Z33 and flywheel shaft) and then drive flywheel and
gear Z51. Under the joint action of the flywheel and one-way
bearing, the rotating speed of the axis 5 can ensure very stable.
Finally, the stable relative rotation of the rotor and stator is
implemented by the gear pairs Z51-Z52. The rotating speed of the
rotor of TENG is controlled by the vibration frequency of the
spring leaf and the number of the ratchet teeth. In other words,
the output speed is controllable, stable, and continuous, which has
nothing to do with the external excitation frequency, direction,
and amplitude.
The electric energy conversion processes are shown in Fig. 1c,
which is based on the triboelectrification effect and electrostatic
induction. Three flexible films are made by fluorinated ethylene
propylene (FEP), in which one end of the film is attached to the
outer wall of the rotor, and the other end slides between adjacent
copper electrodes A1 and A2. In the initial state, the FEP film
completely covers the electrode A1, as
shown in Fig. 1c(I). Because of the triboelectrification effect,
the FEP film obtains negative induced charges, and electrode A1
receives posi- tive charges. When the FEP film slides from A1 to
A2, the electrons flow from A2 to A1 by electrostatic induction, as
shown in Fig. 1c(II). When the FEP film arrives at the position
that completely overlaps with elec- trode A2, the electrons
completely change to A1, ensuing in the positive charges on
electrode A2, as shown in Fig. 1c(III). When the rotor con- tinues
rotating, the electrons flow back to A2 from A1, as shown in Fig.
1c ().
The escapement-spring-leaf mechanism, just like the hairspring
system and escapement of the mechanical watch, is sketched in Fig.
1d. The hairspring system and escapement are innovatively
integrated into an escapement-spring-leaf mechanism, that not only
guarantees the ki- netic characteristics but also shortens the
transmission chain and re- duces the loss of energy in the
transmission process. Detailed operation process of the
escapement-spring-leaf mechanism is sketched to show in Fig. 1d.
The initial status of the escapement-spring-leaf is shown Fig. 1d
(I), there is no external excitation input to the spring leaf
system. The ratchet Z41 rotates clockwise under the drive of the
gear Z32. Meanwhile, the ratchet Z41 transmits the external force
to the escapement lever Z42. Finally, the balance of the spring
leaf vibration subsystem is broken, so that the escapement lever
and mass block swing clockwise, as shown in Fig. 1d(I-II). At the
same time, the restoring moment of the spring leaf is triggered by
its deformation. The direction of the moment is opposite to the
motion direction of the escapement lever and mass block, so the
moment will hinder the movement of the escapement lever and mass
block, and makes their angular velocity decrease gradually. When
the escapement lever rotates to the right limit, the restoring
moment of the spring leaf achieves the maximum, as shown in Fig.
1d(II-III). The escapement lever and mass block gradually move to
the equilibrium position, because the restoring moment is
transformed into the angular velocity of the escapement lever and
mass block in this process. When the escapement lever and mass
block reach the equilibrium position again, the spring leaf is
completely relaxed. Therefore, the restoring moment achieves zero
and the angular velocity accomplishes the maximum. They will go
beyond the equilibrium position and rotate the left limit under
inertia, as shown in Fig. 1d(III-). In this way, the control of the
ratchet Z41 is realized, that is, the controlled release of the
elastic potential energy of the spiral spring is demonstrated. The
floor plan and whole structure of the CO-TENG are shown in Fig. 1e
and f, respectively.
3.2. Performance of the CO-TENG
In CO-TENG, the rotor speed plays an important role in electrical
output characteristic, especially the short-circuit current.
Furthermore, from the previous analysis of the CO-TENG, it can be
seen that the controlled release of the elastic potential energy of
the spiral spring is achieved by the intermittent opening and
closing of the escapement lever Z42 to control the rotation of the
ratchet Z41. Therefore, the fre- quency T0 of the escapement lever
Z42 is the key factor to control the rotor. According to the
kinetic law and the rational mechanics, angle frequency ω of the
escapement lever Z42 is denoted by
ω =
M0
J0
(1)
Where J0 is the rotational inertia of the mass block (the mass of
the escapement lever is much smaller than the mass of the mass
block, it is ignored); M0 is the stiffness of the spring leaf, M0
is expressed as
M0 = Ebh3
12L (2)
Where E, b, h, L is elastic modulus, width, thickness, and working
length of the spring leaf, respectively.
Therefore, the frequency of the escapement lever Z42 T0 is
G. He et al.
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(3)
In our experimental device, the frequency of the escapement lever
Z42 was designed as 2 Hz. In order to further discuss the influence
of other factors on the speed, different spiral spring stiffnesses,
tooth numbers of the ratchet Z41 were studied when external
excitation and frequency of the escapement-spring-leaf is constant.
The rotor speed, running time and short-circuit current of the
CO-TENG under constant excitation as shown in Fig. 2. The
excitation amplitude is 20 mm and the frequency is 0.5 Hz. Fig. 2a,
b, c shows the effect of the different tooth numbers on the rotor
speed under the same spiral spring stiffness. The tooth numbers are
15, 18 and 21, and spiral spring stiffnesses are 1.24, 2.93 and
7.15N⋅mm/rad, respectively. Significantly, it can be found that the
rotor speed is almost constant under different spiral spring
stiffnesses with the same tooth numbers (relative error of the
speed <1%), while the rotor speed has slumped from 169 to 129
rpm as the tooth numbers increase from 15 to 21. This demonstrates
that the rotor speed has nothing to do with the spiral spring
stiffnesses, and is determined by the tooth numbers of the ratchet
Z41. On the other hand, we tested the short- circuit current (Isc)
of the CO-TENG under the same experimental con- ditions, as
demonstrated in Fig. 2d, e, f. The Isc has a considerable
decrease from 6 μA to 4 μA as the tooth numbers increase from 15 to
21 and there is a comparatively small variation at different spiral
spring stiffnesses with the same tooth numbers. In order to obtain
a reasonable spiral spring stiffness parameter, the influence on
the CO-TENG is further discussed, as shown in Fig. 2g, h, i.
Notably, the rotor running time of the CO-TENG is affected by it,
which as the stiffness increases, the running time raises. Hence,
under the comprehensive consideration of rotor speed and running
time, in our experimental device, the spiral spring stiffness is
set to 7.15N⋅mm/rad, and tooth numbers of the ratchet Z41 is
15.
In order to demonstrate the feasibility of the CO-TENG’s working
under random external excitation, the electrical output
characteristic of the CO-TENG, such as open-circuit voltage (Voc),
short-circuit current (Isc) and transfer charge (Qsc), under random
frequency and amplitudes was studied, as shown in Fig. 3. Fig. 3a,
b, c shows the output perfor- mance at different frequencies with a
fixed amplitude of 20 mm. Fig. 3d, e, f display the output
performance at different frequencies with a fixed amplitude of 35
mm. Fig. 3g, h, i demonstrate the output performance at different
frequencies with a fixed amplitude of 50 mm. Noticeably, the
CO-TENG still has a stable output when external excitation
conditions are random and disordered.
Based on the above experiment, the CO-TENG confirms that a
stable
Fig. 2. Rotor speed, running time, and short-circuit current of the
CO-TENG under fixed excitation conditions. Top row: Rotor speed
under different numbers of ratchet teeth and same spiral spring
stiffness; Middle row: Short-circuit current response to different
numbers of ratchet teeth and same spiral spring stiffness; Bottom
row: Running time on different numbers of ratchet teeth and same
spiral spring stiffness.
G. He et al.
5
electrical output characteristic is conceivable even with random
inputs. Therefore, we further explored the application prospects of
the CO- TENG in ambient natural environments. First, energy
harvesting from wave energy was demonstrated, the output
performance and the experimental device are shown in Fig. 4a, b, c
and Fig. 5a (harvesting wave energy to power a thermometer as shown
in Video S1, Supporting Information). A simulated wave with an
amplitude of 20–50 mm and a frequency of 0.5–2.0 Hz was generated
by the wave pool. At this time, the wave energy collected by the
oscillating buoy (inset in Fig. 5a) is transmitted to the CO-TENG
through the rack-and-gear. Obviously, the electrical output
characteristic of the CO-TENG is stable and continual under random
and irregular waves, indicating the effectiveness of the CO-TENG in
addressing random and low-frequency waves. Second, the CO-TENG
harvesting wind energy was confirmed, while the output
characteristic is shown in Fig. 4d, e, f, and the experimental
device is shown in Fig. 5b (collecting wind energy to power a
thermometer as shown in Video S2, Supporting Information). The
breeze which wind speed is 3.5–9.8 m/s is simulated by an air
compressor. The wind energy collected by the wind scoop (bottom
inset in Fig. 5b) is transmitted to the CO-TENG through the
transmission shaft. As will be readily seen, the CO-TENG still has
steady and sustaining output when it works under a random breeze,
demonstrating the feasibility of the CO-TENG in
harvesting random wind energy. At last, it is demonstrated that the
CO- TENG collects random water flow energy, the output performance
is shown in Fig. 4g, h, i, and the experimental device is shown in
Fig. 5c (harvesting water flow energy to power a thermometer as
shown in Video S3, Supporting Information). The water flow of the
experiment is 2.7–10.5 m/s is generated by the submersible pump.
The input shaft of the CO-TENG is rigidly connected to a water
turbine (bottom inset in Fig. 5c), which can harvest random water
flow. Consequently, it is proved that the CO-TENG can still realize
stable output under random water flow, which is feasible.
Synthesize the above experiment, the CO- TENG, which applying
simulated natural environments, can continu- ously and steadily
translate the mechanical kinetic energy to electric energy, and
provides potential solutions for the industrial application of
TENGs.
Supplementary material related to this article can be found online
at doi:10.1016/j.nanoen.2021.106195.
Fig. 5d shows the duration for CO-TENG to charge different com-
mercial capacitors with capacitances of 2.2, 4.7, 10, and 22 μF to
5 V, which apply random wind energy. To prove the CO-TENG use as a
stable power at random external excitation, which was connected to
LEDs and a 22 μF capacitor. The alternating current generated by
CO-TENG is converted into direct current by the rectifier filter.
Fig. 5e displays that
Fig. 3. Performance of the CO-TENG for harvesting random mechanical
energy. (a-c) Electric output characteristic at different
frequencies with a fixed amplitude of 20 mm; (d-f) electric output
characteristic at different frequencies with a fixed amplitude of
35 mm; (g-i) electric output characteristic at different
frequencies with a fixed amplitude of 50 mm; (a), (d), (g)
open-circuit voltage; (b), (e), (h) short-circuit current; (c),
(f), (i) transfer charge.
G. He et al.
6
the 22 μF commercial capacitor was charged via the CO-TENG to
operate a commercial thermometer. Moreover, 450 LEDs in serial
connection were lit up continuously and steadily by the CO-TENG, as
shown in Fig. 5f (Video S4, Supporting Information). This
demonstration shows that the CO-TENG can be regarded as a stable
power supply for MEMS, regardless of changes in the external
environment.
Supplementary material related to this article can be found online
at doi:10.1016/j.nanoen.2021.106195.
4. Conclusion
In summary, we have successfully demonstrated the feasibility of
the CO-TENG, which can steadily and continually release electric
energy through a process of harvesting-storage-release without
manual inter- vention although the original energy is random and
low-frequency. The process is based on a flat spiral spring,
escapement-spring-leaf, and one- way shafting. At the same time,
the CO-TENG has been successfully applied to harvest the power from
random waves, wind, and water flows through the adjustment of the
input gear train and energy collection parts, such as water
turbine, wind scoop, and oscillating buoy. In addition, under
random and low-frequency experimental conditions, the CO-TENG has
been steadily and continuously generated an open-circuit voltage of
550 V, a short-circuit current of 6 μA and transferred
charges
of 190 nC. After using the rectifier filter, a commercial
thermometer and 450 LEDs in serial connection were separately
powered by the CO- TENG. Therefore, this study illustrates that the
CO-TENG can be regar- ded as a potential solution regulated usage
of the random and low- frequency mechanical kinetic energy,
providing an innovative approach for utilization of high entropy
energy.
CRediT authorship contribution statement
Declaration of Competing Interest
The authors declare that they have no known competing financial
interests or personal relationships that could have appeared to
influence the work reported in this paper.
Fig. 4. Demonstration the electrical output characteristic of the
CO-TENG for harvesting ambient natural environments. (a-c)
Electrical output characteristic under random wave energy; (d-f)
electrical output characteristic under random wind energy; (g-i)
electrical output characteristic under random water energy.
G. He et al.
7
Acknowledgment
This research work was financially supported by Program of Basic
Research and Frontier Technology of Chongqing Science and Technol-
ogy Commission (cstc2018jcyjAX0519).
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Prof. Gaofa He received the B. S., M.S. and Ph. D. degrees from
Chongqing University in 1995, 2005 and 2010 respectively. He was a
visiting scholar in the Department of Nanomechanics at Tohoku
University in Japan from 2006 to 2007 and from 2012 to 2013,
respectively. Currently, he is a professor at School of Mechanical
and Power Engineering, Chongqing University of Science &
Technology. His research interests are precise mea- surement,
triboelectric nanogenerator, and sensing technology.
G. He et al.
9
Yingjin Luo received his B.E. degree from Chongqing Uni- versity of
Science & Technology in 2019. Now, he is a post- graduate
student at Chongqing University of Science & Technology.
Currently, his research interests are mainly focused on energy
harvesting for self-powered systems.
Dr. Yuan Zhai received the B.S. and Ph.D. degrees from Chongqing
University in 2007 and 2013, respectively. Now, he is a lecturer at
Chongqing University of Science & Technology. Currently, his
research interests are TENG energy harvester, triboelectric
nanogenerators, energy efficiency optimization.
Prof. Ying Wu is currently a professor at Chongqing University of
Science and Technology. She achieved her Ph.D. degree in the
College of Optoelectronic Engineering at Chongqing Uni- versity.
Her research interests include micro/nano devices, IOT technology,
smart sensors and image processing.
Jing You received her B.E. degree from Yangtze Normal Uni- versity.
Now, she is a postgraduate student at Chongqing Uni- versity of
Science & Technology. Currently, her research interests are
mainly focused on triboelectric nanogenerators.
Rui Lu received her B.E. degree from Chongqing University of
Science & Technology in 2017. Now, she is a postgraduate
student at Chongqing University of Science & Technology.
Currently, her research interests are mainly focused on energy
harvesting for self-powered systems.
Shaokun Zeng received his B.S. degree from Chongqing Uni- versity
of Science & Technology in 2016. Now he is an assistant
experimenter at Chongqing University of Science & Technol- ogy.
Currently, his research interests are mainly focused on mechanical
design and manufacturing.
Prof. Zhong Lin Wang received his Ph.D. from Arizona State
University in physics. He now is the Hightower Chair in Ma- terials
Science and Engineering, Regents’ Professor, Engineer- ing
Distinguished Professor and Director, Center for Nanostructure
Characterization, at Georgia Tech. Dr. Wang has made original and
innovative contributions to the synthesis, discovery,
characterization and understanding of fundamental physical
properties of oxide nanobelts and nanowires, as well as
applications of nanowires in energy sciences, electronics,
optoelectronics and biological science. His discovery and
breakthroughs in developing nanogenerators established the
principle and technological road map for harvesting mechanical
energy from environment and biological systems for powering
personal electronics. His research on self- powered nanosystems has
inspired the worldwide effort in academia and industry for studying
energy for micro-nano- systems, which is now a distinct
disciplinary in energy research and future sensor networks. He
coined and pioneered the field of piezotronics and
piezophototronics by introducing piezoelectric potential gated
charge transport process in fabri cating new electronic and
optoelectronic devices. Details can be found at:
http://www.nanoscience.gatech.edu.
G. He et al.
1 Introduction
2.2 Characterization and measurements
3 Results and discussion
3.2 Performance of the CO-TENG
4 Conclusion